Compact Elliptical Exercise Machine with Adjustable Stride Length

ABSTRACT

An elliptical exercise machine and methods for using the machine where the horizontal length of the stride of the ellipse can be adjusted by the user without the user having to alter the vertical dimension of the ellipse by an equivalent amount. The machine provides for alteration due to the interaction of two arms via a coupler where distance from a rotational axis to the coupler may be adjusted The machine may allow for this adjustment to occur during the performance of an exercise routine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of and is a Continuation of U.S. Utilitypatent application Ser. No. 11/185,179 filed Jul. 20, 2005 and currentlypending, which is in turn a Continuation-in-Part of U.S. Utility patentapplication Ser. No. 10/636,316 filed Aug. 7, 2003 and now U.S. Pat. No.7,097,591 , which in turn claims benefit of U.S. provisional patentapplication Ser. No. 60/401,638 filed Aug. 7, 2002. The entiredisclosure of all these documents is herein incorporated by reference

BACKGROUND

1. Field of the Invention

This disclosure relates to the field of elliptical exercise machines. Inparticular, to elliptical exercise machines which allow for alterationin the shape of the foot path.

2. Description of the Related Art

The benefits of regular aerobic exercise on individuals of any age iswell documented in fitness science. Aerobic exercise can dramaticallyimprove cardiac stamina and function, as well as leading to weight loss,increased metabolism and other benefits. At the same time, aerobicexercise has often been linked to damaging effects, particularly tojoints or similar structures where the impact from many aerobic exerciseactivities can cause injury. Therefore, those involved in the exerciseindustry are continuously seeking ways to provide users with exercisesthat have all the benefits of aerobic exercise, without the damagingside effects.

Most low-impact aerobic exercises have traditionally been difficult toperform Many low-impact aerobic exercises (such as those performed inwater) traditionally require performance either outside or at a gym.Cold weather, other undesirable conditions, and cost can make thesetypes of aerobic exercise unobtainable at some times and to some people.In order to allow people to perform aerobic exercises without having togo outside or to gyms or the like, fitness machines have been developedto allow a user to perform aerobic exercises in a small area of theirhome.

Many of these machines, however, are either too physically demanding onthe user or too complicated to use. In either case, the machine fallsinto disuse. Recently, a class of machines which are referred to as“elliptical machines” or “elliptical cross-trainers” have become verypopular due to their ease of use and their provision of relativelylow-impact aerobic exercise.

Generally in these types of machines, a user performs a motion usingtheir legs that forces their feet to move in a generally ellipticalmotion about each other. This motion is designed to simulate the motionof the feet when jogging or climbing but the rotational motion is“low-impact” compared to jogging or climbing where the feet regularlyimpact a surface. In an elliptical machine, a user uses a fairly naturalmotion to instead move their feet through the smooth exercise patterndictated by the machine. This motion may also be complemented by themmoving their arms in a reciprocating motion while pulling or pushingvarious arms on the machine whose motion is connected to the motion ofthe feet, and vice-versa.

Currently, the biggest problem with elliptical machines is that thedimensions of the elliptical pathway followed by the user's feet aregenerally severely limited in size and shape by the design of themachine The elliptical pathway generated by these machines is oftencreated by the interaction of a plurality of different partial motions,and attempts to alter the motion of a user in one dimension generallyalso alters the motion in another. It is desirable that users have theoption to arrange the machine so that the ellipse can be tailored to fittheir stride and to change during the exercise, but with machines on themarket today, that generally is not possible.

The problem is most simply described by looking at the elliptical motionthe feet make when using an elliptical exercise machine. This ellipticalmotion can be described by the dimensions of the ellipse. Since usersgenerally stand upright on elliptical machines, the user's feet travelgenerally horizontally relative to the surface upon which the machinerests. This represents the user's stride length or how far they step.Further, the user's feet are raised and lowered relative to the surfaceas they move through the ellipse. This is the height to which the user'sfeet are raised. How a user steps depends on the type of action they areperforming. A more circular ellipse will often correspond more to themotion made while climbing, a slightly more elongated ellipse is moreakin to walking, while a significantly elongated ellipse can be moreakin to the motion of running.

As a user's speed on the machine increases or decreases, the resistanceimparted by the machine increases or decreases, or simply based on thesize of the user, it can be desirable for the machine to alter the typeof stride the user is making (by elongating or shortening the stride) tobetter correspond to a more natural movement. This allows the user tomove through a range of different activities during an exercise session,providing for a beneficial workout.

In elliptical machines currently, the size and shape of the ellipse isgenerally fixed by the construction of the machine. That is, thefootrests (the portion of an elliptical machine that will traverse thesame ellipse as the user's feet) are generally forced to proscribe onlya single ellipse when the machine is used and that ellipse is generallyunchangeable. Some machines allow for some alteration of this ellipse,but generally those machines increase both dimensions of the ellipse,not just the horizontal component. That is, the user can adjust thetotal size of the ellipse, but the ratio of the ellipse's componentsremains relatively constant.

This arrangement means that many users are not comfortable with thestride of an elliptical machine as it is either too long or too shortfor their stride. Even if the stride is adjustable, the user may stillbe uncomfortable. For some users, the stride will be much too shortcompared to their normal stride and attempts to increase the stridelength result in their feet being raised uncomfortably high (e g.turning a walking or jogging exercise motion into more of a climbingmotion), while for others the same machine's stride can be much too long(resulting in overstretching of their legs as if they are running allthe time). Further, a user may desire to tailor the machine's motion forthe general type of exercise they want to perform (e.g., more joggingmotion or more climbing motion) and may wish to alter the motion duringan exercise session to have a more varied workout.

SUMMARY

Because of these and other problems in the art, described herein, amongother things, are elliptical exercise machines where the length of thehorizontal dimension (stride) of the ellipse can be adjusted by the userindependent of altering the vertical dimension of the ellipse by anequivalent amount This is generally referred to as having an “adjustablestride length” in the elliptical machine. Further, the machinesdescribed herein are generally intended to allow for alteration of thestride length during the exercise or “on-the-fly” so that a user canvary their stride length throughout an exercise to make the exercisemore comfortable and to provide for a more varied workout.

Described herein, among other things, is an elliptical exercise machinecomprising: a frame; at least two crankshafts rotationally connected tothe frame; a rail attached to the crankshafts so that the rail traversesa path in conjunction with the rotation of the crankshafts; a pendulumarm, connected to the frame at a first rotational axis to the frame, andoperatively connected to at least one of the crankshafts such that thependulum arm reciprocates within a first arc segment as the at least oneof the crankshafts rotates; a footskate, the footskate capable ofreciprocating movement on the rail; an adjustment arm, the adjustmentarm connected to the frame at a second rotational axis, spaced from thefirst rotational axis, the adjustment arm being operationally attachedto the footskate via an interface located toward the distal end of theadjustment arm so that reciprocation of the adjustment arm through asecond arc segment is translated into the reciprocating movement of thefootskate, and a coupler connecting the adjustment arm to the pendulumarm so that when the pendulum arm reciprocates about the firstrotational axis, the adjustment arm is forced to reciprocate about thesecond rotational axis; the coupler being spaced a first distance fromthe first axis and a second distance from the second axis, wherein, atleast one of the first distance and the second distance is variable,

In an embodiment of the machine, the second distance is variable and maybe varied by moving the second rotational axis relative to the framewhile keeping the coupler fixed relative to the frame. The movement maybe accomplished by an adjustment mechanism which may be, but is notlimited to, an electrically powered device, a hand powered device, or aworm screw.

In an embodiment of the machine, at least one of the crankshafts isattached to a flywheel or a resistance device. A computer may be used tocontrol the machine such as by controlling the resistance device and theadjustment mechanism.

In an embodiment of the machine, at least one of the crankshaftsincludes a wheel and an offset pin, the offset pin being rotationallyconnected to a drive link; the drive link being operatively connected toa rocker bar such that: rotation of the wheel causes the drive link toreciprocate which in turn causes the rocker bar to reciprocate, which inturn causes the pendulum arm to reciprocate,

In an embodiment of the machine the position of the rail at any selectedpoint of rotation, is parallel to the position of the rail at any otherselected point of rotation.

There is also disclosed herein, a method of altering the stride lengthof an elliptical exercise machine during an exercise, the methodcomprising: providing an elliptical exercise machine; the machineincluding: a frame; at least two crankshafts rotationally connected tothe frame; a rail attached to the crankshafts so that the rail traversesa path in conjunction with the rotation of the crankshafts; a pendulumarm, connected to the flame at a first rotational axis to the flame, andoperatively connected to at least one of the crankshafts such that thependulum arm reciprocates within a first arc segment as the at least oneof the crankshafts rotates; a footskate, the footskate capable ofreciprocating movement on the rail; an adjustment arm, the adjustmentarm connected to the frame at a second rotational axis, spaced from thefirst rotational axis, the adjustment arm being operationally attachedto the footskate via an interface located toward the distal end of theadjustment arm so that reciprocation of the adjustment arm through asecond arc segment is translated into the reciprocating movement of thefootskate; and a coupler connecting the adjustment arm to the pendulumarm so that when the pendulum arm reciprocates about the firstrotational axis, the adjustment arm is forced to reciprocate about thesecond rotational axis; the coupler being spaced a first distance fromthe first axis and a second distance from the second axis; having a userexercise on the elliptical exercise machine; and adjusting the seconddistance while the user is exercising.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front perspective view of an embodiment of a compactexercise machine with adjustable stride length with the frame cover inplace.

FIG. 2 shows the embodiment of FIG. 1 with the cover removed.

FIG. 3 shows a rear perspective view of the embodiment of FIG. 2

FIG. 4 shows a detail view of the crankshafts. FIG, 4A shows the frontcrankshaft while FIG. 4B shows the rear.

FIG, 5 shows the embodiment of FIG. 2 positioned for two differentstride lengths FIG. 5A is a short stride length, while FIG. 5B is a longstride length.

FIG. 6 shows a general diagram indicating motion of the pendulum arms tothe adjustment arms at a first distance between the axes. FIG. 6A showsthe forward position while FIG. 6B shows the rearward.

FIG. 7 shows a general diagram indicating motion of the pendulum arms tothe adjustment arms at a second distance between the axes. FIG. 7A showsthe forward position while FIG. 7B shows the rearward.

DESCRIPTION OF PREFERRED EMBODIMENT(S)

Although the machines, devices, and methods described below arediscussed primarily in terms of their use with a particular layout of anelliptical exercise motion machine utilizing two rotational crankshaftsand handgrip pendulum arms, one of ordinary skill in the art wouldunderstand that the principles, methods, and machines discussed hereincould be adapted, without undue experimentation, to be useable on anelliptical motion machine which generates its elliptical motion throughthe use of other systems.

The invention disclosed herein primarily relates to elliptical exercisemachines where a reciprocating footskate which traverses a fixed linearportion of a main drive link is replaced by a system where the lineartraversal is adjustable during an exercise to allow for quick andconvenient alteration of the horizontal stride length of the userutilizing the machine, without significantly altering their verticalstride height on the machine,

For the purposes of this disclosure, the terms horizontal and verticalwill be used when referring to the dimensions of the ellipse drawn bythe user's feet. One of ordinary skill in the art will understand thatdepending on the arrangement of the parts and how the machine is used,the ellipse traversed by the user's feet may be at an angle to thevertical and horizontal. That is, a line connecting the two axes of theellipse may not be completely horizontal or completely vertical, or insome cases it may be. For the purposes of this disclosure, when thehorizontal dimension of the ellipse is referred to, it is referring tothe longest dimension of the ellipse (line through both axes), and thevertical dimension is the shortest dimension of the ellipse (line evenlyspaced between the two axes) These dimensions are not used to strictlymean horizontal and vertical relative to the earth. Further, most ofthis discussion will refer to the operation of a single side of anexercise machine, one of ordinary skill in the art would understand thatthe other side will operate in a similar manner.

Further, while the system discusses elliptical motion, it should berecognized that that term, as is used in the art of exercise machines,does not require the foot of the user to traverse a true ellipse, butthat the foot of the user traverses a generally elliptical Or similarrotational shape,. The shape will generally not be circular, but may becircular, oval, elliptical, in the shape of a racetrack, kidney-shaped,or in any other shape having a relatively smoothly curving perimeterwith a horizontal and vertical component of movement.

FIG, 1 depicts an embodiment of a compact elliptical motion exercisemachine (10) including an adjustable stride length of the type that maybe adjusted during the exercise. The exercise machine (10) is comprisedof a frame (50) of generally rigid construction which will sit stably ona surface to provide for the general shape of the machine (10) as shownin FIG. 1. The frame (50) is generally constructed of strong rigidmaterials such as, but is not limited to, steel, aluminum, plastic, orany combination of the above. The frame (50) may be of any shape, butwill generally be designed to provide a place to attach the remainingcomponents and to provide a structure which can resist damage orbreakage from repeated use by the individual exercising thereon. Theframe (50) will also generally be designed so as to stably support auser utilizing the exercise machine (10) and prevent the machine fromhaving undue sway or other undesirable motion while the user isexercising. In the depicted embodiment, frame (50) includes three majorsubstructures, left and right main supports (52) and (53), crossbeams(54), and vertical riser beams (56) and (57).

The main supports (52) and (53) will generally rest on the surface uponwhich the exercise machine (10) is placed This surface will generally beflat. One of ordinary skill in the art would understand that the surfaceneed not be flat as the position of the machine is only importantrelative to the user but, for clarity, this disclosure will presume thatthe machine is placed on a generally flat surface. The main supports(52) and (53) are then held at a position spaced apart from each otherby the crossbeams (54). There may be any number of crossbeams and thedepicted number of four by no means required. The vertical riser beams(56) and (57) extend generally away from the surface on which themachine is resting and generally extend from the main supports (52) and(53) at a point around the front of the frame (50). The vertical riserbeams (56) and (57) will generally be topped by a top crossbeam (58)which may have attached thereto a computer control panel (72) forcontrolling the functions of the machine (10) as known to those ofordinary skill in the art.

The top crossbeam (58) may have additional uses from simply supportingthe computer control panel (72),. In particular, the top crossbeam (58)may be used to support the user's hands during exercising if they do notwish to utilize the exercise arms (201). Still further, the adjustmentmechanism (90), which is discussed in detail later, may be attached tothe top crossbeam (58) in a central location. This attachment providesfor a simplified mechanism for adjusting the second axis (223) as theaxes for both adjustment arms (251) may be arranged at a central point,allowing a single adjustment mechanism (90) to simultaneously operate onboth.

In an embodiment, the frame (50) may include additional components, ornot include any of the above components. Further, any portion of theframe (50) may be covered by a cover (13) as shown in FIG. 1 which maynot provide for specific strength and support of the other components ofthe machine (10), but may serve to cover operating or moving parts ofthe machine (10) for aesthetic or safety purposes such as to keep anindividual's clothing from becoming trapped in the machine (10) orsimply to give the machine a particular “look,”

FIGS. 2 and 3 show various views of the frame (50) with the cover (13)removed so that internal parts are visible. Attached between the mainsupport beams (52) and (53) are a pair of crankshafts (101) and (103).The front crankshaft (101) is arranged generally toward the front of themachine (10) while the rear crankshaft (103) is arranged toward therear. Front and rear are arbitrarily assigned, but relate generally tothe user's usual facing when using the exercise machine (10). Eachcrankshaft (101) and (103) rotates relative to the frame (50) about acentral axis (102) and (104) as is best seen in the depiction of thecrankshafts (101) and (103) shown in FIG. 4. On the front crankshaft(101), there is a wheel (121) attached at each end which will rotate inconjunction with the rotational motion of the front crankshaft (101).The crankshaft (101) or (103) will be attached to the frame (50) throughbearing assemblies around the axial portions (113) of the crankshaft(101) or (103).

Turning back to FIG. 4 and the front crankshaft (101), the frontcrankshaft (101) comprises the axial portions (113) of the shaft, twocrank arms (115) which are generally 180 degrees separated, two crankpins (117), each of which is arranged generally parallel to the axis ofrotation of the crankshaft (101), and a connecting web (119) between thetwo crank pins (117) The resultant design of crankshaft (101) thereforehas the two crank pins (117) arranged generally 180 degrees out of phasewith each other. The rear crankshaft (103) as shown in FIG. 4B willgenerally have a similar arrangement of axial portions (113), crank aims(115), crank pins (117) and connecting web (119). The remainingstructure of the rear crankshaft (103) will, however, be different inmost cases as various components need only interact directly with one ofthe crankshafts.

Attached towards the ends of the axial portions (113) of the frontcrankshaft (101) is a wheel (121) Each wheel (121) has attached thereonan offset pin (123) which is arranged at a distance from the center ofrotation of the wheel (121) to which it is attached. The offset pin(123) on the left side of the machine (10) will generally be arranged soas to be at a position 180 degrees different from the offset pin (123)on the right side of the machine (10) at any given time. Further, theoffset pin (123) will generally be arranged to “trail” the rotation ofthe associated crank pin (117) (that is the crank pin (117) on the leftside on the machine (10) for the offset pin (123) on the left side ofthe machine (10)) about 60 degrees when the crankshafts (101) and (103)are rotated in their generally forward direction.

Each of these offset pins (123) is attached to a drive link (125) whichwill extend from the pin (123) upward to a rocker bar (127). The rockerbar (127), is attached via a rotational connection to a point upward onthe vertical riser (56) or (57). Therefore, as the front crankshaft(101) rotates in the generally forward direction, the wheel (121)rotates with the crankshaft (101) and causes the offset pin (123) torotate in a continuous circle. As the offset pin (123) rotates, thedrive link (125) will generally cause the rocker bar (127) to rock backand forth through a fixed portion of an arc.

Attached to the rocker bar (127) is an exercise arm (201). The exercisearm (201) will generally comprise two portions, the upper portion orhandgrip (203) and the lower pendulum arm (252). Both portions willgenerally be rigidly attached both to each other and to the rocker bar(127) so as to move as a unit. The hand grip (203) at the top of theexercise arm (201) generally moves in a vertically arranged arc segment.This handgrip (203) is designed to be grasped by a user and can be usedto help exercise the user's arms and to drive the motion of thecrankshafts (101) and (103).

In operation, the two crankshafts (101) and (103) are preferably placedin the frame (50) in such a manner that they are rotating at a similarrelative position. That is, the crank pin (117) on the right side of thefront crankshaft (101) is in the same arcuate position as the crank pin(117) on the right side of the rear crankshaft (103) at any instant intime. This arrangement is what is depicted in FIGS. 1 through 3 andprovides that each of the rails (401), which is arranged to be attachedsimultaneously to both the same side crank pins (117) of bothcrankshafts (101) and (103), will move in a pattern whereby it isparallel to its position at any other time during rotation Thisarrangement is not, however, required, and in an alternative embodiment,the crankshafts (101) and (103) are placed to be slightly out of phasewith each other. If placed out of phase, the rails (401) will perform alevering motion about a central pivot point as the crankshafts (101) and(103) rotate

The two same side crank pins (117) on the crankshafts (101) and (103),as discussed above, are each connected by a rail (401). The rail (401)is attached to the appropriate crank pin (117) toward the similar end ofthe rail (401) through a support pivot (403) The support pivot (403)provides a single axis of rotation relative to each of the crankshafts(101) and (103) and allows the rail (401) and the crank pin (117) tofreely rotate about each other at that axis of rotation As thecrankshafts (101) and (103) are connected by the rails (401), it shouldbe apparent that as each of the crankshafts (101) and (103) movesthrough the circle of rotation, the rails (401) force the other of thecrankshafts (101) and (103) to move through the circle at a similarrate. Still further, any point on either rail (401) transcribes a circleat the same time that each of the crank pins (117) transcribes a circle.The two crankshafts (101) and (103) are therefore arranged to operate insimultaneous rotational position. Further, due to the design of thecrankshafts (101) and (103), the two rails (401) will be essentiallyarranged to rotate 180 degrees out of phase with each other.

As the crankshafts (101) and (103) transcribe the circle moving therails (401) through circles, the front crankshaft (101) will turn thewheels (121), which will, in turn, cause the pendulum arms (201) toreciprocate. By placing the user's feet directly on the rails (401), theuser will be able to exercise with the machine (10) with their feettranscribing circular motion in a constantly parallel position. Thiscircular motion may be made elliptical by providing a footskate (501)which will slide on the rail (401) at a particular rate related to theinstantaneous position of the rail (401). Such sliding motion allows foralteration of the travel path from that of a circle to one approachingan ellipse. Traditionally, this elliptical motion was provided in afixed fashion whereby the reciprocation of the rocker bar's (127) wassimply transferred to the footskates (501) by the distal end of thependulum arms (252). One such arrangement of components is shown in U.S.Pat. No. 6,835,166, the entire disclosure, of which is hereinincorporated by reference,

In addition to providing the basic rotational motion to the footskates(501), the crankshafts (101) and (103) may also additionally operate onother components to provide for additional functionality in the exercisemachine (10) For example, the front crankshaft (101) may turn a sprocket(not shown) which is connected to one axial portion (113) thereof. Thesprocket in turn is connected to a chain (not shown) or othersynchronization device, such as, but not limited to, a connecting rod,which connects between the front sprocket and a rear sprocket which isattached to the rear crankshaft (103) at a similar axial portion (113).The rotation of the chain about the sprockets can further help tomaintain synchronicity in the movement of the two crankshafts (101) and(103) by allowing the motion of one crankshaft (101) or (103) to betranslated to the other crankshaft (101) or (103). This can supplementthe rails (401) translation of motion from one crankshaft (101) or (103)to the other and help maintain synchronicity.

There may also be included a variety of other components as is known tothose of ordinary skill in the art for improving exercise motion uponwhich at least one of the crankshafts (101) or (103) interacts. Forexample, the wheel (121) or another wheel on either crankshaft (101) or(103) may be connected to a flywheel (not shown) by means of a belt (notshown) so as to provide for more fluid and smooth motion of the rails(401) as the crankshafts (101) and (103) are rotated and the pendulumarms (201) are reciprocated. The inclusion of such a flywheel is wellknown to those of ordinary skill in the art and allows for the storageof inertial energy so that once the rails (401) have begun to rotate,the rotation is maintained in a smooth fashion.

Further, there may be a resistance device (not shown) included toprovide for resistance to the motion of the wheel (121) and therefore toincrease the difficultly of the exercise. The resistance device maycomprise a friction belt which serves to resist the rotation of thewheel (121). As the belt is tightened on the wheel (121), the amount offorce required to move the wheel (121) (and to maintain its steadyrotation) is increased providing for a more difficult exercise. Thisdesign of resistance device is by no means required, however, and anytype of resistance device, including but not limited to, frictiondevices, electromechanical devices, pneumatic or hydraulic devices, or acombination of devices may be used to provide resistance.

While not shown, the exercise machine (10) may also include an electricdrive or electric assist mechanism. While the exercise motion preferablyuses motion of the arms and legs of the user to drive the crankshafts(101) and (103) through their desired motion as the provision ofexercise, it is recognized that in some cases, a user may lack therequisite strength to commence the exercise or to comfortably performit. Such an assistance mechanism for use in conjunction with arm driventreadmills, which could be adapted for use with this elliptical machine(10), is shown in U.S. patent application Ser. No. 60/613,661, theentire disclosure of which is herein incorporated by reference.

As discussed above, so as to provide for elliptical instead of circularmotion of the user's foot, each of the rails (401) has located thereon afootskate (501) which is arranged to reciprocate on a foot track (503)which is located on the rail (401). The reciprocating relationship maybe accomplished by any mechanism known to those of ordinary skill in theart including sliding or rolling relationships. In the depictedembodiment, the footskate (501) includes a series of wheels (511) whichroll on the foot track (503) as depicted. In the depicted embodiment theadjustable motion is accomplished by the inclusion of an adjustment arm(251) connected via a transfer arm (253) attached toward the distal end(255) of adjustment arm (251) to the front of the footskate (501). Theadjustment arm (251) is rocked in a pendulum motion by the action of acoupler (261) which is located a first distance (231) from the firstaxis of rotation (221) of the pendulum arm (252). The coupler (261) isalso attached a second distance (233) from the second axis of rotation(223) about which the adjustment arm (251) rotates. So as to provide foradjustment to the stride distance during the exercise, at least one ofthe first distance (221) and second distance (223) is adjustable, aswill be discussed in more detail later.

To understand the motion imparted to the footskate (501) and how toadjust that motion, it is best to begin generally with a particularvalue of the first distance (231) and second distance (233) chosen, thisis best seen by examining FIGS. 5 through 7. As the pendulum arm (252)reciprocates due to the front crankshaft (101), the motion of thependulum arm (252) is translated to the adjustment arm (251) via thecoupler (261). The placement of the coupler (261) spaced from the secondaxis of rotation (223) forces the adjustment arm (251) to reciprocate ina related fashion relative to the second axis (223). The motion,however, will generally be altered by the relative position of the firstaxis (221) to the second axis (223) and the second axis (223) to thecoupler (261),

The adjustment arm (251) is attached so as to rotate about a second axisof rotation (223). This second axis of rotation (223) is physicallycreated in the depicted embodiment by rotational attachment of theproximal end of the adjustment arm (251) to the rotational bar (931)which is attached to the adjustment mechanism (90). The second axis ofrotation (223) is preferably parallel to and spatially separated fromthe first axis of rotation (221) about which the pendulum arm (252)rotates. While spatial separation could be in any direction, it ispreferable that the axes be vertically separated and be arranged so thatthe second axis of rotation (223) is located within the area traversedby the pendulum arm (252). It is more preferred that the second axis(223) be located vertically displaced from the first axis of rotation(221) so as to be below the first axis of rotation. It is still morepreferred that the second axis (223) be essentially below the first axis(221) so as to simplify the motion relationship between the pendulumarms (201) and adjustment arms (251) Such an arrangement is depicted inFIGS. 5 through 7 as it allows the pendulum arms (201) and adjustmentarms (251) to simultaneously have horizontal motion in the samedirection. This correspondence generally makes it easier to maintainreinforcement of the rotational movement of the crankshaft (101) or(103) by horizontal movement of the footskate (501). With a non-verticalarrangement, the same modifications can still be accomplished, but theinterrelationship becomes unnecessarily complicated.

FIGS, 6 and 7 demonstrate the relationship of the motion of the pendulumarm (252) to the adjustment arm (251). The motion relates because of thepercentage of arc length, and the actual arc length traversed by distalend (255) of the adjustment arm (251), compared to the coupler (261). Asshown in the FIGS., the coupler (261) helps to dictate the relationshipdue to its positioning below both the first axis (221) and second axis(223). As can be seen from FIG. 6, the coupler (261) comprises arotational pivot allowing both the pendulum arm (252) and the adjustmentarm (251) to rotate about their individual axes (221) and (223)respectively, while the coupler (261) also serves to transfer rotationalmotion from one of the two arms, but at a different rate. The two arms,however, rotate through different arc segments. The coupler (261) willgenerally be located at a fixed distance from one of the two axes (221)or (223). At least one axis of rotation will be arranged, however, so asto be moveable relative to the coupler (261). In the depictedembodiment, the second axis (223) is moveable while the first axis (221)is fixed. As this movement occur's, the second distance (233) istherefore either shorted or lengthened,

FIGS. 6 and 7 show together how this can affect the motion of theadjustment arm (401). In FIG. 6 there is shown two circles. The firstcircle (1261) has a radius of R₁ while the second circle (1251) has aradius of R₂ where R₂ is greater than RI. Further the axis of circle(1261) is vertically transposed above the axis of the circle (1251) by adistance D. The circle (1251) corresponds to the path of the distal endof the adjustment arm (251) while the circle (1261) corresponds to thepath of the coupler (261) At the instant shown in FIG. 6A there is aline drawn to each of the circles representing the portion of thependulum arm (252) above the coupler (261) and the adjustment arm (251).As you can see at the forward position of FIG. 6A, the coupler (261) hasrotated through a certain arc segment as indicated by the portion of thecircle (1261) in solid line form. Further, the rotation of the coupler(261) has effectively forced the distal end (255) of the adjustment arm(251) to traverse a greater arc as shown by the portion of circle (1251)in solid line. In effect, due to arcuate motion of each portion about adifferent axis, and the interaction of the coupler (261) to thestructure of the two different parts, the coupler (261) is increasingthe amount of rotation traversed by the distal end (255) of theadjustment arm (251) over what it would traverse if the second axis(223) of rotation was coaxially arranged with the first axis (221). Ofparticular importance, the distal end (255) of the adjustment arm (251)has moved a greater distance horizontally, which is the component ofmotion which will be transferred to the footskate (251), than it wouldhave moved had it been rotating about the first axis (221),

Comparing FIG. 6 to FIG. 7, as the distance between the second axis andthe coupler (261) decreases, the horizontal length traced by theadjustment aim (251) will increase with the same arcuate distancetraversed by the pendulum arm (252). Obviously, when moving in theopposite direction, the opposite is true. A comparison of FIG. 6 to FIG.7 shows how the amounts of arc traversed by the distal end (255) of theadjustment arm (251) (and the vertical and horizontal components of thattraversal) changes based on the location of coupling (261) or secondaxis (223). In this case the second axis (223) is moved to a greaterdistance D₂ from the first axis (221). It should be apparent that themovement of the second axis (223) is not required to adjust thehorizontal distance. In an alternative embodiment, the coupler (261) maybe moved instead. A related effect can also be achieved by moving thefirst axis (221) while holding the second axis (223) and coupler (261)in position. This, however, generally requires a more complicatedrelationship to provide similar motion.

As should be clear from the simplified drawings of FIGS. 6 and 7, thedual arm arrangement shown in FIGS,1 through 3 allow for the footskate(501) to be provided with an alterable reciprocation on the main drivelink (401) by adjustment of the relative spacing of the second axis(223) and coupler (261). In particular, as the second axis (223) andcoupler (261) are moved together, the amount of horizontal distancetraversed by the distal end (255) of the adjustment aim (251)necessarily increases FIG. 5 shows an embodiment of the movement and itseffect on the extreme position of the footskate (501) using a partialview of the machine (10) of FIGS. 1 through 3.

The result of this adjustment is to alter the stride length of theexercise. This is accomplished by altering the distance of reciprocationof the footskate (501) without altering the underlying motion of themain drive link (401). It is, therefore, desirable to include structureto implement such transfer There is included a transfer arm (253), whichserves to transfer the horizontal component of the adjustment arm's(251) reciprocation to the footskate (501). The transfer arm (253) isrotationally connected between the distal end (255) of the adjustmentarm (251) and to the footskate (501) in a manner such that some of theadjustment arm's (251) motion is translated to the footskate (501) Asshould be apparent, as the reciprocation of the pendulum arm (252) isdirectly related to the rotation of the front crankshaft (101), and thereciprocation of the pendulum arm (252) is in turn related to thereciprocation of the adjustment arm (251) which is in turn related tothe translation of the footskate (501), the footskate (501) willoscillate on the main drive link (401) in a relatively fixed timingrelationship with the rotation of the front crankshaft (101) Therefore,the system can provide for a relationship of translation related to theposition of motion of the front crankshaft (101). To put this anotherway, for any selected instant along the rotation of the front crankshaft(101), the instantaneous motion of the footskate (501) is the sameregardless of the number of times the rotation is repeated.

With appropriate timing, the reciprocation of the footskate (501) maycomplement the motion of the main drive link (401) to increase thehorizontal dimension of the ellipse, or may work against thereciprocating motion of the main drive link (401) to decrease thehorizontal dimension of the ellipse In the latter case, it may even bepossible to rotate the major dimension of the ellipse to be in thevertical direction by making the horizontal reciprocation smaller thanthe original circular radius. In particular, if one were to select aparticular fixed point, the reciprocating motion of the footskate (501)allows the user's foot to traverse a distance across that fixed point sothat the user's foot has always moved a particular distance relative tothe fixed point for a particular location on the ellipse. As the defaultmotion of the footskate (501) in a fixed position is a circle, theinterrelationship will generally be selected so as to have thereciprocation work constructively with the horizontal component of therotation. In this way, the horizontal movement component of the maindrive link (401) at any moment is in the same instantaneous direction asthe horizontal component of the adjustment arm (251).

This reciprocating motion of the adjustment arm (251), provides for anarrangement that provides for elliptical as opposed to circular motionfor the user's feet. At the same time, once this relationship isdetermined (which is generally based on the positioning of the offsetpin (123)), the adjustment mechanism allows the length of the exerciseto become adjustable.

This design provides for an adjustable horizontal stride distancewithout a corresponding increase in vertical stride height during theexercise by allowing adjustment of the relative position of the secondaxis (253) relative to the coupling (261). This adjustment may occur byeither moving the coupling (261) or by moving the second axis (223) asboth types of motion are equivalent. As the crankshaft (101) and (103)motions are not altered, the vertical dimension of the exercise is notaltered.

To adjust the dimensions of the exercise in the embodiment of FIGS. 1through 3, the machine (10) of the depicted embodiment provides foradjustment of the position of the second axis (223) as shown in FIG. 5.In particular, as can be seen in the detail views of FIG. 5, the secondaxis (223) is provided as part of an adjustment mechanism (90). This maybe any type of adjustment mechanism (90) but in the preferred embodimentis designed to be a rotational bar (931) which provides a linkage to theadjustment arm (251) and defines the second axis (223). The rotationalbar (931) is adjustably mounted to the frame. Generally, movement of therotational bar (931) relative to the flame is accomplished by ahydraulic or pneumatic piston, worm screw, linear adjuster, or othertranslation device (935) which is in turn powered by an electric orother engine (not shown). The engine may be powered by electricitygenerated by the user's performance of the exercise, or may be from anexternal source. In an alternative embodiment, the adjustment mechanism(90) may include a hand crank, may be physically lifted by the userbetween different predetermined positions, or may comprise lockingpoints for the rotational bar (931) to be moved by physical lifting ofthe user, or may be moved by any other type of lift mechanism (90) knownnow or later discovered

Movement of the rotational bar (931) relative to the flame will serve tomove the second axis (233) both relative to the frame (50) and eithercloser to or further away from the coupler (261) as the coupler (261) isin fixed positional relationship to the flame (50) This allows the userto adjust the stride length. To keep the relationships simpler, theadjustment mechanism (90) will generally move the bar within a verticallinear path, but that is by no means required The adjustment mechanism(90) can be used by the machine (10) in conjunction with the exercisebeing performed to provide for “on the fly” adjustment of the stride.This in-exercise adjustment allows for increased functionality of themachine (10), comfort for the user, and control over the availableexercise options.

In an embodiment, the machine (10) will utilize the adjustable stridevia the control panel (72) which will be used to select exercisecharacteristics. Generally, the user will preselect a program ofexercise which corresponds to various different types of motion to beperformed according to a pattern, over time, and the control panel (72)will adjust the stride length and resistance device to provide fordifferent types of comfortable motion at different times in the exerciseprogram.

In particular, the user may start off with a warm up period of lightwalking, then go into an alternating period of fast running and slowerclimbing, and then end with a period of slower cool down. The device cancreate this exercise by beginning with a period of intermediate stridelength at a relatively low speed of rotation and low resistance. Thiswould conform more to a quick walk. The user can then be instructed tospeed up the stride and as the user's stride begins to accelerate, themachine can adjust the stride length to be longer and lower theresistance. Further, as the length is increasing, the user willnaturally wish to adopt a more comfortable, and faster, motion. Thiswould conform more to a running motion. The user can then be instructedto slow up their stride as the machine starts to decrease the stridelength and in fact may reduce the stride length to a more circularmotion while increasing the resistance. This provides for a more of aclimbing motion As the user enters the cool down section, the stridelength can again be adjusted more toward the middle stride length orwalking motion again.

While the invention has been disclosed in connection with certainpreferred embodiments, this should not be taken as a limitation to allof the provided details. Modifications and variations of the describedembodiments may be made without departing from the spirit and scope ofthe invention, and other embodiments should be understood to beencompassed in the present disclosure as would be understood by those ofordinary skill in the art.

1. An elliptical exercise machine comprising a frame; at least twocrankshafts rotationally connected to said frame; a rail attached tosaid crankshafts so that said rail traverses a path in conjunction withthe rotation of said crankshafts; a pendulum arm, connected to saidframe at a first rotational axis to said frame, and operativelyconnected to at least one of said crankshafts such that said pendulumarm reciprocates within a first arc segment as said at least one of saidcrankshafts rotates; a footskate, said footskate capable ofreciprocating movement on said rail; an adjustment arm, said adjustmentarm connected to said flame at a second rotational axis, spaced fromsaid first rotational axis, said adjustment arm being operationallyattached to said footskate via an interface located toward the distalend of said adjustment arm so that reciprocation of said adjustment armthrough a second arc segment is translated into said reciprocatingmovement of said footskate; and a coupler connecting said adjustment armto said pendulum arm so that when said pendulum arm reciprocates aboutsaid first rotational axis, said adjustment arm is forced to reciprocateabout said second rotational axis; said coupler being spaced a firstdistance from said first axis and a second distance from said secondaxis; wherein, at least one of said first distance and said seconddistance is variable.
 2. The machine of claim 1 wherein said seconddistance is variable
 3. The machine of claim 2 wherein said seconddistance is varied by moving said second rotational axis relative tosaid frame while keeping said coupler fixed relative to said frame. 4.The machine of claim 3 further comprising an adjustment mechanism formoving said second rotational axis relative to said frame.
 5. Themachine of claim 4 wherein said adjustment mechanism is electricallypowered.
 6. The machine of claim 4 wherein said adjustment mechanisminclude a worm screw.
 7. The machine of claim 4 wherein at least one ofsaid crankshafts is attached to a flywheel.
 8. The machine of claim 4wherein at least one of said crankshafts is attached to a resistancedevice.
 9. The machine of claim 8 further comprising a computer tocontrol said machine.
 10. The machine of claim 9 wherein said computercan control said resistance device and said adjustment mechanism. 11.The machine of claim 4 wherein said adjustment mechanism is handpowered.
 12. The machine of claim 1 wherein at least one of saidcrankshafts includes a wheel and an offset pin, said offset pin beingrotationally connected to a drive link said drive link being operativelyconnected to a rocker bar such that: rotation of said wheel causes saiddrive link to reciprocate which in turn causes said rocker bar toreciprocate; which in turn causes said pendulum arm to reciprocate. 13.The machine of claim 1 wherein the position of said rail at any selectedpoint of rotation, is parallel to the position of'said rail at any otherselected point of rotation.
 14. A method of altering the stride lengthof an elliptical exercise machine during an exercise, the methodcomprising: providing an elliptical exercise machine; the machineincluding: a frame; at least two crankshafts rotationally connected tosaid frame; a rail attached to said crankshafts so that said railtraverses a path in conjunction with the rotation of said crankshafts; apendulum arm, connected to said frame at a first rotational axis to saidframe, and operatively connected to at least one of said crankshaftssuch that said pendulum arm reciprocates within a first arc segment assaid at least one of said crankshafts rotates; a footskate, saidfootskate capable of reciprocating movement on said rail; an adjustmentarm, said adjustment arm connected to said flame at a second rotationalaxis, spaced from said first rotational axis, said adjustment arm beingoperationally attached to said footskate via an interface located towardthe distal end of said adjustment arm so that reciprocation of saidadjustment arm through a second arc segment is translated into saidreciprocating movement of said footskate; and a coupler connecting saidadjustment arm to said pendulum arm so that when said pendulum armreciprocates about said first rotational axis, said adjustment arm isforced to reciprocate about said second rotational axis; said couplerbeing spaced a first distance from said first axis and a second distancefrom said second axis, having a user exercise on said ellipticalexercise machine; and adjusting said second distance while said user isexercising.